1. Field of the Invention
The present invention relates generally to toilet systems and, more particularly, to overflow prevention devices for toilets.
2. Description of the Related Art
Although significant advances have been made in toilet technology, particularly in reducing the amount of water needed for flushing purposes, a satisfactory solution for preventing the overflow of a toilet in the event of a blockage of the toilet bowl, or associated waste plumbing, has not been achieved.
Prior art overflow prevention arrangements have tended to be complex and often require a customized toilet design or significant modification of a standard toilet. For example, as disclosed in U.S. Pat. No. 6,052,841, one prior art solution utilizes a water level sensor and an electric motor to close a valve thereby preventing a flow of water from the toilet tank to the bowl in response to an above-normal water level. Such an arrangement is relatively expensive and requires an external source of power to operate the motor. In addition, such an arrangement may be unreliable, especially if the source of power is expendable, such as batteries, for instance.
Another prior art arrangement, disclosed in U.S. Pat. No. 4,170,049, utilizes a water level sensor in the form of a float to sense an above-normal water level. The float is connected to a stop that is configured to move with the float. The stop moves to a position tending to contact the standard toilet flush valve, or flapper valve, when the float detects an above-normal water level, thereby inhibiting opening of the flush valve. Although such an arrangement eliminates the need for external power, the closure force acting on the flapper valve is limited to the force that is developed by the float. Accordingly, it may be possible for a user to overcome the closure force provided by the stop by forcefully manipulating the toilet handle. In addition, such an arrangement requires a lever assembly to operatively connect the float with the stop member, which results in an undesirably complex device.